Method and apparatus for sewing with a presser foot



Dec. 12, 1967 L. KALMAN 3,357,386

METHOD AND APPARATUS FOR SEWING WITH A PRESSER FOOT Filed June 14 1965FIG! FIG. 2

United States Patent 3,357,386 METHOD AND APPARATUS FOR SEWING WITH APRESSER FOOT Leo Kalman, 2731 Taylor St., Dallas, Tex. 75226 Filed June14, 1965, Ser. No. 463,562 9 Claims. (Cl. 112-235) ABSTRACT 0F THEDISCLOSURE Method and apparatus for accomplishing the result of movingmaterial under the presser foot of a sewing machine by applying a fluidpressure onto the material from the presser foot, and simultaneouslycooling the sewing needle with a jet stream.

This invention relates generally to sewing machines and moreparticularly to a method and apparatus for applying pressure from thepresser foot to hold the cloth against the feed dogs or teeth of themachine to advance the cloth under the needle.

A primary object of this invention is to provide a method for permittingcloth to be advanced through a sewing machine that does not require theapplication of mechanical pressure to the cloth.

Another principal object is to provide a means for permitting cloth tobe advanced through a sewing machine in such a way that no damage can beimparted to the cloth. 7

Another object is to provide a means whereby a presser foot may beconstructed or an existing presser foot may be modified to permit thecloth to be advanced through a sewing machine without physical contactbetween the presser foot and the cloth.

A further object is to provide a method by which the medium of air maybe utilized to provide the holding force to permit the cloth to beadvanced by the feed dogs of a sewing machine.

An additional object is to provide an arrangement whereby compresed airis directed through a presser foot and against the cloth being worked tohold the cloth against the feed dogs of a sewing machine to that thecloth may be fed therethrough by the conventional feed mechanism.

And a still further object is to provide a presser foot for sewingmachines that is similar to and interchangeable with a conventionalpresser foot but which includes provision for directing air through thefoot and against the cloth being worked for the purpose described.

And yet another object is to provide a presser foot having a perforatedbottom surface and means for directing pressurized air through'theperforations to engage a cloth underneath.

And another object isv to provide a presser foot mechanism wherein theinterior of the presser foot is is hollow and the bottom surface isperforated and wherein compressed air is directed into the hollowinterior and out through the perforations when desired.

And still another object is to provide an arrangement whereby a standardpresser foot may have a perforated air tube attached to its bottomsurface and may have a perforated shoe attached to the air tube in sucha way that compressed air may flow through the tube and out through theperforations in the shoe for the purpose disclosed.

And an object of this invention is to provide a means wherebydifferential pressure between the top of the cloth being worked and thebottom of the cloth permits the cloth to be advanced through a sewingmachine by conventional means.

3,357,385 Patented Dec. 12, 1367 An object is also to accomplish thefunction of a presser foot without the use of spring pressure.

Another object is to provide a means in a presser foot structure toprovide an air cushion between the foot and the cloth to reduce frictiontherebetween.

An additional object is to provide a needle coolant and a means fordelivering the coolant to the needle in operation.

These and other objects and advantages will be apparent from anexamination of the following specification and drawing in which:

FIGURE 1 represents a side elevational view of the presser foot assemblyapparatus of this invention.

FIGURE 2 is a front elevational view of the device 01 FIGURE 1.

FIGURE 3 is a bottom plan view of the device of I FIGURES 1 and 2.

FIGURE 4 is an elevational cross sectional view of the device of FIGURE1 installed and operating, showing a cloth being sewn in the practice ofthis invention.

FIGURE 5 is a side elevational view of another embodiment of the deviceof FIGURE 1.

Referring now more particularly to the characters of reference on thedrawing it will be observed that the presser foot apparatus of thisinvention indicated generally at 2 consists basically of a verticalshank 3 to which is pivoted at 4 a horizontally extending foot member 5,and in contradistinction to conventional presser feet, a rearwardlyextending fluid conduit 6.

Examining the individual parts in closer detail in FIGURES 1 and 5 it isseen that the shank 3 includes a vertical channel 7 on one side and arelatively short vertical slot 8 on the opposite side, bothconfigurations being included to permit this conventional shank to fit astandard industrial sewing machine. The lower end of the shank 3 isreduced to a small neck at 9 and is enlarged again at 10 to receivepivot pin 4 through an opening 11 (FIG. 4). The lower rear of enlargedarea 10 includes a recess 12 which retains a coil spring 13, also shownin FIGURE 4.

The foot 5 is similar in external appearance to a conventional presserfoot, but the foot 5 of this invention includes an enlarged internalcavity 14 that extends from the rearmost section of the body ofthe footout into a portion of the two forwardly extending toes 15, as seen inFIGURES 3 and 4. The bottom surface of foot 5 includes a plurality ofopenings 16 that connect the internal cavity 14 with the outsidesurface. And the facing vertical sides of the toes 15 include horizontalopenings 17 for a purpose to be described hereafter.

The fluid conduit 6 is physically connected to and integral with thefoot 5, and the hollow interior 18 of the conduit is in communicationwith the cavity 14. This construction permits a flexible air hose (notshown) to be connected to conduit 6 via fitting 20 and permits air orother fluid to be selectively introduced through conduit 6 and intocavity l4 under pressure by means of well known apparatus. When themedium (air or other fluid) arrives in cavity 14 under pressure itimmediately passes through the openings 16 and 17 at a reduced butsubstantial pressure and at an increased velocity.

In operation the entire presser foot apparatus 2, being installed on anotherwise conventional industrial sewing machine, is lowered in theusual manner to the vicinity of the cloth or other material to be sewn.However in this operation the bottom surface of foot 5 does notordinarily touch the material, indicated at 21 and 22 in FIGURE 4. Butrather the material 21 and 22 is resting one on the other and bothoverlying a sewing machine plate 23. Sewing machines of this type areequipped with feed dogs or jaws 24 which reciprocate in an opening suchas 25 in plate 23 to advance the material 21 and 22 through the machineand past the needle, indicated at 26. However in conventional machinesthe advance of cloth is achieved by the physical pressure of the bottomof the presser foot against the top of the material on one side and bythe grip of thefeed dogs on the other side. The grip of the dogs ismaintained throughout the stroke of the dogs by virture of the physicalpressure asserted by the presser foot. There is a tendency however whenopposing physical pressures are exerted on a material and where one ofthe forces is applied through sharp or abrupt teeth for the material tobe damaged. This tendency is eliminated in the present invention by theuse of a fluid pressure to provide the backup needed to permit the feeddogs to carry out their normal function.

The desired fluid pressure is applied when needed by well known fluidcontrol apparatus (not shown). For example after the layers of materialto be sewn have been laid over the plate and under the needle, and afterthe foothas been lowered to the vicinity of, but not necessarilytouching the material, the fluid, preferably air, is directedunderpressure through the tube interior 18 and into cavity 14 fromwhence it passes out through openings 16 to apply sufiicient pressure tothe top side of material 21 to create a pressurized area between thematerial and the foot as indicated at 27. The feed dogs 24 are thus ableto function to advance both materials 21 and 22 through the machinewithout requiring any direct physical contact by the foot against thematerial.

The pressurized medium performs another valuable function in thisinvention also. In sewing at high speeds on heavy materials the sewingmachine needle heats up to a temperature that both shortens the life ofthe needle and makes it more subject to breakage than an ordinary needleat room temperature. This detrimental heating has been substantiallyreduced by the employment of the small orifice horizontal openings 17which direct a high velocity air stream or jet onto the needle while itis operatmg.

In the embodiment shown in FIGURE 5, a conventional presser foot F hasbeen modified in such a manner to permitthe achievement of the desiredresults of this invention. The foot F is attached at its underside tothe flattened end 30 of a fluid conduit 6A. A perforated shoe 31 is thenattached to the underside of the flattened end 30. A series ofperforations in the flattened section 30 are aligned with theperforations in the shoe 31, so that pressurized fluid in conduit 6Awill pass out through both sets of perforations and will hold thematerial down against the feed dogs 24. Laterally projecting holes 17Amay be drilled in the flattened section 30 before it is installed ontopresser foot 'F.

It will be observed that the foregoing description and drawing havedisclosed a unique and novel presser foot apparatus which will providethe advantages enumerated but without the inherent disadvantages ofconventional presser foot arrangements. It is understood that changesmay be made which come within the spirit of this invention and all suchchanges or modifications are considered to fall within the scope of theappended claims.

What is claimed is:

1. A method for sewing material, comprising in combination the steps of:directing pressurized air through perforations in the bottom of a sewingmachine presser foot and against the material in such a manner as tohold the material in place, advancing the material through a sewingmachine, and simultaneously directing a coolant air in a high velocityflow against the sewing machine needle.

2. In a sewing machine, a presser foot apparatus including a presserfoot, means for advancing material through said machine, said presserfoot including a hollow interior and including at least one opening thatis small relative to the dimensions of said foot between said interiorand the bottom of said foot, and means for directing pressurized airthrough said hollow interior and out through said bottom opening, andwherein said at least one opening comprises a series of perforations.

3. In a sewing machine, a presser foot apparatu including a presserfoot, a means for advancing material to be sewn through said machine,and means attached to said presser foot for applying fluid underpressure between the entire presser foot and material in such a mannerthat no part of the foot rests on the material.

4. An apparatus as in claim 3 wherein said fluid is compressed air.

5. In a sewing machine, a presser foot apparatus including a presserfoot having projecting toes, a conduit attached to said foot, said footdefining at least one side opening in saidtoes and including a bottomdefining at least one opening therein, said foot structure defining ahollow interior and said presser foot apparatus defining a continuoushollow internal path through said conduit, through said interior,through said side opening and through said bottom opening.

6. In a presser foot apparatus, a presser foot, a separate conduitmember attached to the underside of said presser foot and a shoe memberattached to the underside of said conduit.

7. In a presser foot apparatus, a presser foot, a conduit member havingat least one opening physically attached to the underside of said foot,and a shoe member having at least one opening attached to the bottom ofsaid conduit.

8. A presser foot apparatus as in claim 7 wherein each said at least oneopening comprises a series of coincident perforations.

9. A presser foot apparatus as in claim 7 wherein one said at least oneopening in said conduit member is generally horizontal.

References Cited UNITED STATES PATENTS 2,750,908 6/ 1956 Odermann et alll2235 FOREIGN PATENTS 99,205 11/ 1961 Norway. 315,295 8/ 1956Switzerland.

PATRICK D. LAWSON, Primary Examiner,

1. A METHOD FOR SEWING MATERIAL, COMPRISING IN COMBINATION THE STEPS OF:DIRECTING PRESSURIZED AIR THROUGH PERFORATIONS IN THE BOTTOM OF A SEWINGMACHINE PRESSER FOOT AND AGAINST THE MATERIAL IN SUCH MANNER AS TO HOLDTHE MATERIAL IN PLACE, ADVANCING THE MATERIAL THROUGH A SEWING MACHINE,AND SIMULTANEOUSLY DIRECTING A COOLANT AIR IN HIGH VELOCITY FLOW AGAINSTTHE SEWING MACHINE NEEDLE.